Bent axis type axial piston pump or motor

Abstract

A bent axis type axial piston pump or motor wherein the cylinder block is rotatable in synchronizm with the torque plate about an axis inclined relative to the axis of rotation of the torque plate. The shaft of the torque plate passes through the inclined cylinder block without mutual mechanical interference and is supported by bearings at the opposite sides of the casing. The torque plate and the cylinder block are connected by a mechanism which ensures exact synchronization of rotation of the two members. A static pressure balance is established between the working fluid acting on the opposite sides of the torque plate, the cylinder block and the pistons, respectively. The angle of inclination of the cylinder block with respect to the shaft can be changed thereby to change the capacity of the pump or motor. The pump or motor of this invention may be provided in a tandem type.

What we claim is: 
     
       1. A bent axis type axial piston pump or motor comprising: a casing having at least a pair of inlet-outlet ports;   a shaft rotatable about a first axis and having a portion thereof extending within said casing;   a torque plate mounted on said shaft portion for simultaneous rotation therewith about said first axis;   a cylinder block rotatable about a second axis and provided with a plurality of cylinder bores circumferentially arranged about said second axis, each of said cylinder bores having an axis parallel with said second axis and an opening facing an axial end surface of said torque plate;   passage means for communicating said inlet-outlet ports with said cylinder bores for transport of working fluid;   means for supporting said cylinder block so that said second axis intersects said first axis;   said shaft passing through said cylinder block without mutual mechanical interference therebetween;   means for rotatably supporting said shaft at the opposite sides of said cylinder block and said torque plate;   a plurality of pistons each slidably inserted into one of said cylinder bores so as to define a chamber therein and having an outer end projecting therefrom;   means for connecting the outer ends of said pistons to said torque plate so as to enable conversion of torque into hydraulic pressure, or vice versa; and   means for synchronizing the rotation of said torque plate and that of said cylinder block, said synchronizing means comprising: a hollow cylindrical member disposed radially closer to said second axis than said cylinder bores and projecting from said cylinder block toward said torque plate and ending in a plug portion coaxial with said second axis, with said shaft passing through said cylindrical member;   and a socket portion of said torque plate, coaxial with said first axis and receptive of said plug portion, with said plug and socket portions being complementary in shape to enable connection so that they are simultaneously rotatable about said first and second axes and slidable relative to each other about an intersection of said first and second axes.     
     
     
       2. An apparatus as in claim 1, wherein: said plug portion comprises a plurality of fingers each of which is generally shaped as a solid prolate spheroid truncated on opposite ends of a major axis thereof; and   said socket portion comprises a plurality of holes corresponding to and receptive of each of said fingers.   
     
     
       3. An apparatus as in claim 2, wherein: each of said holes is generally cylindrical in shape with a central axis parallel to said first axis.   
     
     
       4. An apparatus as in claim 1, wherein: said plug portion comprises a hollow body having inner and outer external surfaces at least one of which has surfaces intersecting at edge lines so as to generally define, in a transverse section view of said plug portion, a first regular polygon, and said edge lines and surfaces being curved as viewed in longitudinal section; and   said socket portion comprises a generally annular opening having inner and outer internal surfaces at least one of which, in transverse section view of said socket portion, generally defines a second regular polygon complimentary with and slidably receivable of said first regular polygon.   
     
     
       5. An apparatus as in claim 4, and further comprising: slots extending radially between said inner and outer external surfaces of said plug portion and generally midway between and parallel to said edge lines so as to provide fingers of said plug portion; and   walls extending radially into said annular opening of said socket portion, corresponding to and cooperative with said slots of said plug portion.   
     
     
       6. An apparatus as in claim 4, said socket portion further comprising: said means for connecting said pistons to said torque plate.   
     
     
       7. A bent axis type axial piston pump or motor comprising: a casing having at least a pair of inlet-outlet ports;   a shaft rotatable about a first axis and having a portion thereof extending within said casing;   a torque plate mounted on said shaft portion for simultaneous rotation therewith about said first axis;   a cylinder block rotatable about a second axis and provided with a plurality of cylinder bores circumferentially arranged about said second axis, each of said cylinder bores having an axis parallel with said second axis and an opening facing an axial end surface of said torque plate;   passage means for communicating said inlet-outlet ports with said cylinder bores for transport of working fluid;   means for supporting said cylinder block so that said second axis intersects said first axis;   said shaft passing through said cylinder block without mutual mechanical interference therebetween;   means for rotatably supporting said shaft at the opposite sides of said cylinder block and said torque plate;   a plurality of pistons each slidably inserted into one of said cylinder bores so as to define a chamber therein and having an outer end projecting therefrom;   means for connecting the outer ends of said pistons to said torque plate so as to enable conversion of torque into hydraulic pressure, or vice versa; and   means for synchronizing the rotation of said torque plate and that of said cylinder block, said synchronizing means comprising: a hollow cylindrical member projecting from said cylinder block toward said torque plate and ending in a plug portion coaxial with said second axis, with said shaft passing through said cylindrical member, said plug portion comprising a plurality of fingers each of which is generally shaped as a solid prolate spheroid truncated on opposite ends of a major axis thereof;   and a socket portion of said torque plate, coaxial with said first axis and receptive of said plug portion, said socket portion comprising a plurality of holes corresponding to and receptive of each of said fingers, with said plug and socket portions being complementary in shape to enable connection so that they are simultaneously rotatable about said first and second axes and slidable relative to each other about an intersection of said first and second axes.     
     
     
       8. An apparatus as in claim 7, wherein; each of said holes is generally cylindrical in shape with a central axis parallel to said first axis.   
     
     
       9. A bent axis type axial piston pump or motor comprising: a casing having at least a pair of inlet-outlet ports;   a shaft rotatable about a first axis and having a portion thereof extending within said casing;   a torque plate mounted on said shaft portion for simultaneous rotation therewith about said first axis;   a cylinder block rotatable about a second axis and provided with a plurality of cylinder bores circumferentially arranged about said second axis, each of said cylinder bores having an axis parallel with said second axis and an opening facing an axial end surface of said torque plate;   passage means for communicating said inlet-outlet ports with said cylinder bores for transport of working fluid;   means for supporting said cylinder block so that said second axis intersects said first axis;   said shaft passing through said cylinder block without mutual mechanical interference therebetween;   means for rotatably supporting said shaft at the opposite sides of said cylinder block and said torque plate;   a plurality of pistons each slidably inserted into one of said cylinder bores so as to define a chamber therein and having an outer end projecting therefrom;   means for connecting the outer ends of said pistons to said torque plate so as to enable conversion of torque into hydraulic pressure, or vice versa; and   means for synchronizing the rotation of said torque plate and that of said cylinder block, said synchronizing means comprising: a hollow cylindrical member projecting from said cylinder block toward said torque plate and ending in a plug portion coaxial with said second axis, with said shaft passing through said cylindrical member, said plug portion comprising a hollow body having inner and outer external surfaces at least one of which has surfaces intersecting at edge lines so as to generally define, in a transverse section view of said plug portion, a first regular polygon, and said edge lines and surfaces being curved as viewed in longitudinal section;   and a socket portion of said torque plate, coaxial with said first axis and receptive of said plug portion, said socket portion comprising a generally annular opening having inner and outer internal surfaces at least one of which, in transverse section view of said socket portion, generally defines a second regular polygon complimentary with and slidably receivable of said first regular polygon, with said plug and socket portions being complementary in shape to enable connection so that they are simultaneously rotatable about said first and second axes and slidable relative to each other about an intersection of said first and second axes.     
     
     
       10. An apparatus as in claim 9, and further comprising: slots extending radially between said inner and outer external surfaces of said plug portion and generally midway between and parallel to said edge lines so as to provide fingers of said plug portion; and   walls extending radially into said annular opening of said socket portion, corresponding to and cooperative with said slots of said plug portion.   
     
     
       11. An apparatus as in claim 9, said socket portion further comprising: said means for connecting said pistons to said torque plate.